Getting Started
Getting Started with
the Datacasting Feed Reader
The Datacasting Feed Reader is an application used to subscribe and
read RSS 2.0 and Datacasting feeds. This feed reader allows you
to take advantage of the unique metadata included with datacasting
feeds.
Subscribing to Feeds
In order to subscribe to a Datacasting feed, you must first find a feed
to subscribe to. If you haven't got a feed in mind, just click
through the Getting Started tab in the Feed Reader and select the Datacasting Feed Directory link.
This will open a web browser window and
bring you to our online directory. From there you can add a
feed. Let's choose the "QuikSCAT hurricane data" feed under
"Phenomenon".
Now right-click on the link to the feed and copy the link into your
clipboard.
Next, return to the Datacasting Feed Reader and select Feeds -> Add New Feed...
You are now subscribed to the QuikSCAT
Hurricane Ultra High-Res Winds feed. Your reader will now
occasionally check and automatically collect any new articles posted to
this feed.
You can also search Google for Datacasting Feeds, or request that your
favorite data provider start providing a Datacasting Feed.
Viewing Feeds
Now the feed name should be displayed in the upper left panel and a
list of articles should appear in the upper right panel. You can
select one of the articles and then choose the Standard View tab. You should
see something like this:
A preview of the data is shown in the bottom left (if available), and
all of the metadata concerning this data granule is displayed to the
right. You can view the preview more closely by double-clicking
on the
image. More options are available in the preview window with a
right-click. You can also customize the column view in the
article list by selecting
Options -> Customize Column View...
Try adding the wind speed column.
Now sort by descending wind speed by
clicking on the column header twice...
You may even rearrange the columns by dragging the column
heading. All of the information described in the article view is
available to be added as a column. The information is stored in
XML tags and each tag has an easy to read long name in the article view.
All of the tags are also available for filtering as described in the
next section.
Filtering Feeds
The most powerful aspect of the Datacasting Feed Reader is that of
filtering. Filtering allows you to select articles from a feed
based
on the values of the metadata stored in the feed. In order to
create a filter, right-click on the feed you wish to filter.
For example we'll create a filter which selects all data with
Acquisition Start Time after
January 1st, 2008 (2008-01-01 00:00:00 GMT) and with Hurricane Max Wind
Speed greater than 75 knots.
As you can see, this filter collects 18 articles that match the
criteria in this case (your results may vary if new hurricane data has
been added).
You can filter any feed or add a filter to further constrain an
existing filter (see below). When
specifying a filter, you can choose to "Flag on match" or
"Download on match". These will be described in greater detail
below.
Flag on Match
Flagging articles marks them for future attention. It is a way of
reminding you that you think that it might be important. One way
of flagging articles is to simply click in the flagging column of the
article that interests you.
You can also flag articles using a filter
and the Flag on match check-box.
We'll create another filter which is nested within the After 1/1/2008 & > 75 kt Winds
filter to further constrain wind speed and only
select those articles with greater than 100 knot winds and we'll mark
these with a flag. In order to create this nested filter just
right on the parent filter and only those items which are selected by
the parent will be furthered constrained by the nested filter.
These articles are flagged in any view. Even when they are mixed
in with other articles.
Editing Filters
Editing filters works just like creating them. You simply
right-click on the filter and select Edit
Filter. If, for instance, we are only interested in
storms in the South Pacific basin. Based on reading the
data provider's website, we find that the Hurricane Identifier contains "P"
whenever a storm originates in the South Pacific basin.
The resulting filter only selects a single storm, FUNA. This storm matches all
of our nested criteria and is flagged.
Downloading
Once you have identified data of interest, you will likely want to
download it. There are a number of ways to download data
including using a filter, but Download on Match will be covered
later. If you have an article of interest selected, you can
select Download enclosure from
the Articles menu.
Also, clicking the check mark column in the article list will download
the enclosure. This column also indicates the state of the
download; a check in the column means that the data has been
downloaded, a running dog indicated that the data is being downloaded
(fetched), and an X indicates
that the download is incomplete (canceled or failed).
You can check up on the download progress by looking at the Download Manager by going to Options -> Show download
queue... This window shows you all on-going,
completed, failed, or canceled downloads. In this case, it shows
that we successfully downloaded a data granule.
Once files are downloaded, they are stored in the subdirectory download in the directory that you
ran the FeedReader.jar from.
The subdirectory names are formed from the feed name, year, and
month/day that the data granule was published.
Download on Match
Downloading based on a filter match works just like Flag on match
above. In the case of Download
on match any items which match the filter are queued for
download. The Feed Reader can simultaneously download up to 4
files and the remainder are queued. You can check on the status
of the queue in the Download Manager.
Quitting the Feed Reader
You can quit the Feed Reader by clicking on the close window
button. All feeds will be automatically saved and then updated
when you start the application again.
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